Dispatching and scheduling system



- July 10, 1934 c LARSON 1,966,071

DISPATCHING AND SCHEDULING SYSTEM Filed July 31, 1950 5 Sheets-Sheet 1 CAR N 3 3H4 CAP N 1 2.

CAR N 4 4-I4 y 10, 1934- D. c. LARSON 1,966,071

DISPATCHING AND SCHEDULING SYSTEM Filed July 31, 1950 5 Sheets-Sheet 2 f I40 m L- ACTU ATING COlL gmcnm m) M5 XISO FIQZ n 2 L 'INVENTOR BY 4"!!! m' ATTORNEY July 10, 1934. D. c. LARSON 1,966,071

DISPATCHING AND SCHEDULING SYSTEM Filed July C51, 1930 5 Sheets-Sheet 3 IIIIIII Ill CAR CAR N 2 N 5 M93 I Y|76 .H

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566 CHM/1A (3M1 INVENTOR mul'lhim ATTORNEY y 1934- D. C.LAI- $ON 1,966,071

DISPATCHING AND SCHEDULING SYSTEM Filed July 31, 1930 5 Sheets-Sheet 4 7 H65 I aw-WP W B D 9 2%? W BY 7 ATTORNEY? July 10, 1934. D. c. LARSON 1,966,071

DISPATCHING AND SCHEDULING SYSTEM Filed July 31, 1950 5 Sheets-Sheet 5 LATCHEDI 53 t was 5-44 4-50 RES ET cm U (LATCHED m) l-LUbS 2-LU65 -L X I: O 8 13M CW2 Lwvw INVENTOP BY I ATTORNEY Patented July 10, 1934 PATENT OFFICE msra'rcnmc am) sonanumno SYSTEM David Carl Larson, Yonkers, N.

Y., assignor to Otis Elevator Company, New York, N. Y., a corporation of New Jersey Application July 31, 1930, Serial No. 471,926 46 Claims. (Cl. l77336) The invention relates to dispatching and scheduling systems, and particularly to such systems as. applied to a plurality of elevators arranged in a group.

In the operation of a plurality of elevators arranged in a group, it is important that some supervisory control be exercised over them so that eflicient and satisfactory service may be derived therefrom. Supervisory control may be effected manually by an experienced starter who directs his sole attention to the task. The attention of'such a starter, however, is frequently diverted by prospective passengers asking questions and by other causes, all to the impairment of the elevator service. Furthermore, such complete manual supervisory control is always dependent upon the human element, and thus subject to its fatigue, bad judgment, and irregularities. The object of 'this invention is to exercise supervisory control over ,a group of elevators through the medium of mechanical and electrical equipmentthat eliminates the undesirable features of complete manual supervisory control, and that, in addition, incorporates suflicient flexibility to adapt the supervisory functions to the variety of operating conditions that may arise in order to obtain eflicient and satisfactory elevator service. Illustrative of the variety of general operating conditions with which such an equipment must cope, may be mentioned the heavy inward flow of trafllc in the morning, the heavy outward flow of traffic in'the evening, the peak two-way flow of trafllc during the middle of the day, and the normal two-way flow of traffic during other periods of the business day.

In addition, the equipment must cope with numerous other operating conditions some of which are more or less of a transient and varying nature. Such other operating conditions may be due, for

40 example, to temporary deviations from thetrafllc conditions that are average for the time of day under consideration. As a result of these transient and varying operating conditions, one car may consume, during one trip, more than the average time, while a succeeding car may consume, during a similar trip, less than the average time.

The main feature of this invention is the provision of a supervisorycontrol employing automatically operating mechanical and electrical equipment that is capable of effectually coping with the variety of both "the general and transient operating conditions that may arise in a bank of elevator cars during the course of a 5 day.

Other features and advantages will become apparent from the following description and appended claims.

In carrying out theinvention, there is provided means for ordering the operator of each car, when that car is at a terminal floor, to start that car away therefrom. The preferred arrangements, which are those herein described, employ two visual signals within each eat, one signal for ordering the starting of the car from the lower terminal floor, and the other signal for ordering the starting of the car from the upper, terminal floor. There is also provided apparatus for controlling the operation of these start or dispatch signals so that, under certain operating conditions, cars are dispatched normally at regular intervals of time from each of the lower and upper terminal floors.- For flexibility, it is provided that these time intervals may be shortened or lengthened. Provision is made so that if there is no car at a terminal floor eligible to be dispatched at the time that a car normally is dispatched therefrom, the start signal initiated by the apparatus at that instant is maintained effective so that it is given to the car first to arrive at the terminal floor and become eligible to be dispatched. In the event that there has been an excessive delay somewhere so that no car has departed from a terminal floor by the time a given percentage of a time interval has elapsed, it is provided that all timing operations are suspended until a car does leave the terminal floor. As a result of these operations, when they are made effective at both the lower and the upper terminal floors, the supervisory control tends to maintain an even number of cars so that at any instant one-half the cars are operating on an up trip, while the other half are operatingon a down trip. This relationship among the cars may, for convenience, be considered as a bal- 95 anced one. The maintenance of such a balanced" relationship among the cars, it may be seen, provides for equality of service in both directions. As, provision is made to render any number of cars less than the total number in the group subject to the supervisory control, it may, under certain conditions, be desirable to render an odd number of cars subject to the supervisory control. In such event it is provided that a relationship among such an odd number of cars that is analogous to the balanced relationship among the even number of cars may bemaintained. This is elfected upon the operation of a certain switch so that dispatch signals for cars at the upper terminal floor are initiated half an interval after the time when they are normally initiated for an even number of cars. As a result of this displacement in the time at which cars are dispatched from the upper terminal floor, the odd car is, in normal situations, dispatched from the upper terminal floor during the interval between the dispatch of successive cars at the lower terminal floor.

It is further provided that the giving of the dispatch signals at the lower and upper terminal floors may be so interrelated that the scheduled time for a car on an up trip may be made less than, equal to, or' greater than the scheduled time for a car on a down trip.. As a result of this provision, the round trip time may be apportioned in varying percentages between the up and down trips in order to accommodate trailic conditions in any particular building or time of day.

Another provision of the invention is that at each terminal floor the dispatch signal installed by the supervisory control system for that terminal floor is given to one car only of those that may be at that terminal floor at that time. This is effected by providing a system of relays such that when the relay for one car operates, after the arrival of that car at the terminal floor, to render that car eligible to receive a dispatch signal, the relays for all the other cars are rendered inoperative. As a result no other car then at the terminal floor, nor no other car subsequently arriving thereat, is eligible to receive the dispatch signal given to that one car. In addition, provision is made so that one car continues to receive the starting signal until that car has actually departed from the terminal floor. This is effected by providing that the resetting of devices that control the operation oi'. the start signals is accomplished only upon the travel of the car away from the terminal floor. The operator of a car is thus continuously informed, after the dispatch signal is once given to that car, that his car is being ordered to leave the terminal floor, and he cannot cancel the order except upon compliance therewith. 1

There is also provided, in carrying out the invention, means for informing a starter or other supervisory oflicial of the performance of the cars in the group, and of the responsiveness of the car operators. The arrangements illustrated employ two starters lights, one for indicating conditions at the lower terminal floor, and the other for indicating conditions at the upper terminal floor. The arrangements are such that when a dispatch signal is initiated for ordering a car to leave a terminal floor, but at that time no car is at that terminal floor capable of receiving such dispatch signal, the starters light for that terminal floor is caused to illuminate with a steady light. When a car arrives andreceives the dispatch signal, the starters light is caused to illuminate with a flickering light. This flickering of the starters light is caused to continue until the car departs from the terminal floor. As a result, the steady light is a signal that. a dispatch signal is being given, but no car is at hand to receive it; the change from a steady to a flickering light is a signal that a car has arrived and is receiving the dispatch signal; and the continued flickering of the starters light is a signal that the car has not left in response to the order to start. By reference to indicators such as are extant that indicate the positions of the cars, the starter may normally determine which of the cars is receiving the dispatch signal.

Another provision of the invention is that, in the event that it is desired to reduce to a minimum the period during which a car may be at aterminal floor waiting for the expiration of a scheduling interval after the giving of a dispatch signal to the preceding car until this, the succeeding car, may receive a dispatch signal, the dispatch signal may be given to a car immediately upon its arrival at a terminal floor and its becoming eligible to receive such signal. Such an immediate giving of the dispatch signal may be desirable when the traffic in one direction predominates over that in the other, or when the traific is otherwise heavy. This may occur, for example, in the morning, when the traflic is predominately up, with the result that it may be desirable to eliminate the dead waiting time at the upper terminal floor so that the cars may return to the lower terminal floor as quickly as possible. In the evening an analagous situation may arise with respect to. the lower terminal floor, for then the traflic may be predominately down, with the result that it may be desirable to eliminate dead waiting time at the lower terminal floor so that the cars may return to the upper terminal floor as quickly as possible. Such an immediate giving of the dispatch signal for a terminal floor may be effected by the operation of a switch for that terminal floor so that a by-pass circuit is established across a pair of contacts the engagement of which normally controls the initiation of the dispatch signal for that terminal floor. The engagement of these contacts is thus simulated, so that as a result, as soon as a car arrives at that terminal floor and becomes eligible to receive a dispatch signal, a dispatch signal is given to that car.

The invention also provides that, when so desired, the cars may be run wild. Such an operation of the cars may be desired when traffic is abnormally heavy, and it is desired to push the cars to the limit of their capacity. In such event the scheduling interval may be dispensed with at both the lower and the upper terminal floors, and dispatch signals given to each car at each terminal floor as soon as the car arrives at terminal floor and becomes eligible to receive such signals. In the arrangements illustratedsuch an immediate giving of the dispatch signal at both terminal floors may be effected by simultaneously operating the switch described in the preceding paragraph both for the lower and the upper terminal floor.

Under certain conditions it may be desirable to prevent the departure of a car from a terminal floor until the receipt by that car of a dispatch signal, or order to start. In such event it is provided in one of the arrangements illustrated that, as soon as a car arrives at a terminal floor, the starting control circuit for that car may be rendered ineffective for causing the starting thereof. It is further provided that upon the receipt by that car of a dispatch signal, the starting control circuit may be restored to an operative condition. Accordingly with such pro visions, an operator of a car is unable to disobey floor is illuminated to direct prospective passengers to that car. In one of the arrangements illustrated, this operation is effected by placing in the terminal floor hall light circuit for a car a pair of forward contacts of the relay which, upon operation, renders that car eligible to receive a dispatch signal at that terminal floor. As a result, the terminal floor hall light for that car is illuminated when that car becomes eligible to receive a dispatch signal. If desired a notification light, visble to the operator wthin a car, may be provided to notify the operator that his car is the next to be dispatched, and that prospective passengers are being directed to his car. such notification lights, one for each terminal floor, are connected in parallel with the hall light.

for the corresponding terminal floor. As a result each notification light is illuminated at the same time as the corersponding terminal floorhall light.

In the drawings: Y.

Figure 1 is a schematic diagram of a four car elevator bank illustrating one relative position of the cars thereof. Y

Figure 2 is a wiring diagram of a dispatching and scheduling system.

Figure'3 is an elevation of the timing motor and associated mechanism for said system.

Figure 4 is a view along the line 4-4 of Figure 3.

.Figure5 is a detail showing the construction of a roller brush, mounted on the crosshead of a floor selector and also showing a floor selector contact adapted to cooperate with the roller brush.

Figure 6 is a schematic diagram illustrating relative positions of cars in a three car elevator bank.

Figures '7 and 8, taken together, constitute a wiring diagram of a second dispatching and scheduling system,

Figure 9 is a detail showing a modified form of floor selector contact which is preferably employed in the system of Figures 7 and 8, and

Figure 10 is a detail diagrammatically illustrating a switch utilized in the system shown in Figures '7 and 8.

Referring to Figure 1, there is shown a bank of four elevator cars, cars Nos. 1, 2, 3, and 4, operating between two dispatch floors 11 and 12. These dispatch floors are normally, though not necessarily, the first floor and the top floor. The figure illustrates the position and direction of travel of four cars at one instant in the cycle of events as a convenient starting point for the descriptions of the dispatching and scheduling systems that follow. There is provided in each car a suitable control panel on which are mounted the various control switches and signals for that car. For simplicity, Figure 1 illustrates the control panel for each car as mounting only operators control switches 1-13, 2-13, 3-13 and 4-13 for cars Nos. 1, 2, 3, and 4 respectively; up start lights 1-14, 2-14, 3-14 and 4-14 for cars Nos. 1, 2, 3 and 4 respectively; and down start lights 1-15, 2-15, 3-15 and 4-15 for cars Nos. 1, 2-, 3 and trespectively. Suitably positioned so as to be convenient of access for the starter or other ofilcial is a dispatch panel 16 upon which are mounted various hand operated switches and certain other apparatus (not shown) to control the operation of the dispatching and schedulingsystem. These may incude In one of the arrangements illustrated the knife switches 125, 126, 127, 130, 1-51, 2-51, 3-51, 4-51, and the speed control switch 142, which are referred to later in moredetail. Also mounted upon the dispatch panel, or elsewhere so as to be readily visible to the starter or other official, are two starters lights; one designated 1'7, for the lower terminal floor, and the other, designated 18, for'the upper terminal floor.

Figure 2 shows an arrangement of circuit conmotions for dispatching and scheduling the four car bank of Figure 1., In this Figure 2 no attempt is made to show the coilsv and contacts of the various electromagnetic switches in their associated positions, a straight diagram being employed wherein the coils and contacts of the various switches areseparated in such a manner as to render the circuits involved relatively simple. In this diagram, the electromagnetic switches have been given letters in addition to the usual reference numerals, so that although the parts of the switches have been separated for simplicity in showing the circuits, they may still be identified by means of the common letters. To further aid in simplifying the diagram, switches, coils, contacts and other apparatus that correspond for each car are similarly designated, with the exception of prefixes l-, 2-, 3- and 4- to designate the car with which the part is emswitch for car No. 1; .4-15 is the down start light for car No.- 4; 3-44 is the floor selector brush for car No. 3; coil U is the actuating coil of the up schedule relay U; contacts U63are a pair of contacts of the up schedule relay; coil 1-LU64 is the actua'tingcoil of the selective up relay for car No. 1, contacts l-LU67 are a pair of contacts of that relay; coil 2-LU64 is the actuating coil of the selective up light relay for car No. 2; and contacts 2-LU67 are a similar pair of contacts of the corresponding relay for car No. 2. The electromagnetic switches are shown in their deenergizcd positions, hence the contacts thereof that are shown as separated are forward contacts and the contacts that are shown as engagedare back contacts. To further aid the reading of the diagram, all stationary contacts are illustrated in cross section. The designations of the electromagnetic switches are as follows:-

K-Timing motor relay U-Up schedule relay D-Down schedule relay UU-Up dispatching relay DD-Down dispatching relay LU-Selective up light relay LD-Selective down light relay FU-Up flicker relay FD-Down flicker relay In the wiring diagram of Figure 2 there is diagrammatically illustrated a timing motor 20 connected to suitable reduction gearing "21 to drive a shaft 22. Figure 3 shows constructional details of this apparatus. The motor 20, suitably mounted upon a vertical support 23, is arranged above the housing containing the gearing 21. If desired, the gearing, may include a set of spur gears 24 mounted outside of the housing so that a large range of rotational speeds for the shaft 22 may be readily obtained by the interchange of theseispur gears 24 without disturbing the oilimmersed gearing in the housing. The shaft 22 is provided with contact bridges 25, 26 and 27. The bridges are clamped between the jaws of arms 30, 31 and 32, respectively,'from which they are insulated as by means of non-conducting tubes 28. Each arm is adiustably mounted on the shaft 22, as by set screws 33, so that the angular spacing between the arms, and thus the contact bridges, may be set to any desired amount. Figure 4 illustrates one satisfactory angular spacing.

The contact bridges are caused to rotate by the motor 20 in the direction indicated by the arrows in Figures 2 and 4. During the course of this motion starting from the position in which the contact bridges have been shown, contact bridge 25 engages with a set of stationary contacts 34 and 35; contact bridge 26 engages with a set of stationary contacts 36 and 37, and after one-half of a revolution of the shaft 22, with a set of stationary contacts 38 and 39; and contact bridge 27 engages with a set of stationary contacts 42 and 43, and after one-half of a revolution of the shaft 22, with a set of stationary contacts 40 and 41. Each set of stationary contacts comprises two metallic fingers of appropriate design suitably mounted upon the support 23. As may be seen, the engagement of each contact bridge with its stationary set of contacts results in the establishment of a circuit between the stationary contacts, and since the contact bridge is normally rotated at a definite speed, as is hereinafter described, the circuit between the stationary contacts is normally established at regular time intervals.

The wiring diagram of Figure 2 also diagrammatically illustrates selector brushes 1-44, 2-44, 3-44 and 4-44 which travel in accordance with the motions of the cars Nos. 1, 2, 3 and 4 respectively. This correlation of each selector brush with its corresponding car may be effected through the medium of a fioor selector of suitable arrangement in which the selector brush may be mounted upon a travelling crosshead that.

moves in accordance with the motion of the car for which it is provided. When each car is at the lower terminal floor the selector brush for that car engages with a terminal floor selector contact 45, individual to that car, and when each car is at the upper terminal floor the selector brush for that car engages with a terminal floor selector contact 46 individual to that car. These terminal floor selector contacts may be stationarily mounted upon the floor selector at the positions corresponding to the terminals for which they are provided. The selector contacts 45 and 46 are identical except that the upper terminal floor selector contacts 46 are invertedly mounted with respect to the lower terminal floor selector contact 45. Figure 5 shows in more detail a selector brush while in engagement with a lower terminal floor selector contact. To a travelling member 100 there is fastened, as by bolt 99, a U- shaped metallic bracket 101 having arms 102 and 103, the former designated arm being shown as partly broken away. To the ends of these arms there is secured a metallic pin 104. This pin pivotally supports a metallic U-shaped member 105 having a conducting roller 106 rotatably mounted thereupon by a pin 195. A removable locking strip 107 is provided to prevent the dislodgment oi the member 105 from the pin 104. -The member 105 is also provided with an extending strip 108 that extends through a hole in one end of a metallic plate 110. To the other end of plate 110 is rotatably mounted a second conducting roller 111, as by means of pins 196. A compressed spring 112 is positioned between the arms 102 and 103 and arranged so that one of its ends engages the plate 110, and the other of its ends engages the travelling member 100 through the intermediary of an insert member 113. As a result of this construction the spring maintains the conducting roller 111 bearing against the conducting roller 106 and thus tends to rotate the member 105 which mounts the conducting roller 106 counterclockwise until the extending strip 108 engages with the insert member 113 as a stop. When the roller 106 is in engagement with a selector contact, as is shown. in Figure 5, the member 105 is rotated clockwise to compress the spring 112 still further, and thus toinsure, as a result of the bearing of roller 111 against roller 106, an excellent electrical circuit between the selector contact and the bolt 99.

The terminal floor selector contact 45 is supported upon a stationary bar 114 made 0! suitable insulating material. A metallic member 115 fastened to the insulating bar 114 by the bolt 11'! is provided with a lip 116 that is bent over the edge of the bar. This lip is the surface adapted to be engaged by the roller brushes. A pair of lugs 118, provided on the member 115, pivotally support a metallic lever arm 47. A compressed spring 120 is positioned between the member and the lever arm to urge the arm against suitable stops 121. One end of the lever arm 47 projects a short distance outward from the plane of the contact lip 116, the purpose of this construction being more fully described later. The other end of the lever arm is adapted, upon rotation thereof against the spring 120, to suitably engage a contact 48. This contact 48 is mounted upon the insulating bar 114 by a bolt 122 in such a manner that it is insulated from the metallic member 115. For this purpose, a mica or other insulating strip 197 may be employed between member 115 and bar 114 so as to insulate the head of bolt 122 from member 115.

As a result of this construction it may be seen that when the selector brush moves away from engagement with the terminal floor contact lip 116 (in an upward direction for the parts shown in Figure 5), the brush engages the projecting end of the lever arm 47 and causes rotation of the lever arm so that the other end engages the contact 48. The brush then rides around the projecting end of the lever arm, whereupon the spring 120 restores the lever arm to its initial position. When the brush moves toward the terminal floor contact lip 116 (in a downward direction for the parts shown in Figure 5) the brush engages the projecting end of the lever arm, and,

inasmuch as the arm already is urged against the stops 121, rides around the projecting end of the lever arm and then engages with contact lip 116. The upper terminal'floor selector contact 46, being similar in construction and operation to the lower terminal floor selector contact 45 is described only to the extent of pointing out that 4 its lever arm and the contact with which the lever arm is adapted to engage are designated in Figure 2 as 49 and 50 respectively.

The invention-is most readily described by a description of the operation of a system embody-' ing the invention. Such a system is shown by Figure 2. It is initially assumed that the cars are in the positions and are moving in the directions as shown by Figure 1, with the result that the selector brushes 1-44, 2-44, 3-44, and 4-44 are in corresponding positions as shown in Figure 21' It is also assumed that the knife switches 1-51, 2-51, 3-51 and 4-51 are closed so that all four cars are included in the dispatching and scheduling system; that knife switches 125 and 126 are closed, and that knife switch 130 is thrown to the left so that the blades 131 and 132 thereof engage the contacts 133 and 134 respectively. As a result, upon the closing of the double bladed knife switch 127 to connect the dispatching and scheduling system to the plus and minus mains, the timing motor 20 is started. The circuit for the motor field 140 may be traced from the positive main, through the left hand blade of the knife switch 127, wire 137, contacts K52 of the timing motor relay, timing motor field 140, wire 138, right hand blade of the knife switch .127, to the negative main. The circuit for the motor armature 141 may be traced from the wire 137, through contacts K52 of the timing motor 'relay, timing motor armature 141, switch arm 143 of the timing motor speed control switch 142, one of the contacts 144 of the speed control switch, a portion of resistance 145, to wire 138. The speed with which the timing motor runs is dependent upon the amount of the resistance 145 that the speed control switch 142 causes to be included in the circuit just traced. For the arrangement of the resistance 145 as shown, the less resistance that is included in the motor armature circuit above traced, the faster is the speed with which the motor runs.-

The closing of the knife switch 127 also results in the energization of the actuating coil DD53 of the down dispatching relay and of the actuating coil UU54 of the up dispatching relay. The circuit for the coil DD53' may be traced from the wire 137, through wire 146, coil DD53, knife.

switch 125 (which has been assumed to be closed), to wire 138. The circuit for the coil UU54 may be traced from the wire 137, through wire 146, coil UU54, knife switch 126(which has been assumed to be closed), to wire 138. The consequent operation of the down dispatching relay DD causes the engagement of its contacts DD55 and the separation of itscontacts DD56. The engagement of contacts DD55 prepares a circuit to the contacts D60, while the separation of contacts DD56 removes a by-pass around the con tacts D61. The operation of the up dispatchingrelay UU causes the engagement of its contacts UU57 and the separation of its contacts UU58.

The engagement of contacts UU57 prepares a contacts U63.

circuit to the contacts U62 while the separation of contacts UU58 removes a by-pass aroundthe Assume that car No. 1 now arrives at the lower terminal floor. The selector brush '1-44 for that car first engages the end of the lever arm l-47, rides around itas described in connection with Figure 5, then engages with the lower terminal floor selector contact 1-45. The engagement of the selector brush 1-44 with the end of lever arm'1-47 completes a circuit from the wire 137, through the wire 147, knife switch 1-51;

ance X150, and at a predetermined value of current flow the selective up light relay 1LU operates and causes the engagement of contacts 1-LU67 and 1LU68 and the separation of con-.

tacts 1-LU65 and 1LU66. The engagement of contacts 1-LU67 completes a holding circuit for the relay l-LU from the actuating coil 1-LU64 direct to the wire 138. The separation of contacts 1-LU65 and 1LU66 prevent the operation of the selective up light relays LU for all the other cars after the relay LU for the first car operates. The engagement of contacts 1-LU68 prepares a circuit for the up start light 1-14 in car No. 1. tions of operation the circuit for up start light 1-14 is-incomplete at the contacts U-63 and UU58 so that this light is not now illuminated.

It is to be noted that the transfer of contact of the selector brush 1-44 from the end of lever arm 1-47 to the lower terminal floor selector contact 1-45 as car No. 1 reaches the floor level of the lower terminal floor does not break the holding circuit for the actuating coil 1-LU64 of the selective up light relay LU for car No. 1. The holding circuit for this relay when the car is at the lower terminal floor level may be traced from wire 137, through wire 147, knife switch 1-51, selector brush 1-44, selector contact 1--45, coil 1-LU64, contacts 1-LU67, to wire 138. As a result relay l-LU is maintained operated to continue-its functions.

Assume that at about this time car No. 3 arrives at the upper terminal floor. The selector brush 3-44 for that car first engages the endof the lever arm 3-49, rides around it similarly as described in connection with Figure 5, then engages the upper terminal floor selector contact 3-46. The engagement of the selector brush 3-44 with the end of lever arm 3-49 completes a circuit from the wire 137, through the wire 147, knife switch 3-51, selector brush 3-44, lever arm 3-49, selector contact 3-46, actuating Under the assumed condi- I coil 3-LD70 of the selective down light relay for 1 Xlown light relay 3LD operates and causes the engagement of contacts 3-LD73 and 3-LD74, and the separation of contacts 3-LD71 and 3-LD72. The engagement of contacts 3-LD73 completes a holding circuit for the relay 3-LD from the actuating coil 3-LD70 direct to the wire 138. The separation of contacts 3-LD71 and 3-LD72 prevent the operation of the selective down light relays LD for all the other cars after the relay LD for-the third car operates. The engagement of contacts 3-LD74 prepares a circuit for the down start light 3-15 in car No. 3. Under the assumed conditions of operation the circuit for down start light 3-15 is incomplete at the contacts D61 and DD56 so that this light is notnow illuminated.

It is to be noted that the transfer of contact of the selector brush 3-44 from the end of lever arm 3-49 to the upper terminal 3-46 as car No. 3 reaches the floor level of the upper terminal floor does not break the holding circuit for the actuating coil 3-LD70 of the selective down light relay for car No. 3. The holding circuit for this relay when the car is at the upper terminal floor level may be traced from wire 137, through wire 147, knife switch 3-51, selector brush 3-44,

selector contact 3-46, coil 3-LD70, contacts 3-LD73, to Win 138. As a result relay 3-LD is maintained operated to continue its functions.

Assume that after the cars Nos. land 3 have reached the lower and upper terminals, respectively, as described above, the rotation of shaft 22 by the timing motor causes the engagement of contact bridge 25 with the stationary contacts 34 and 35, and the engagement of contact bridge 26 with the stationary contacts 36 and 37. With the illustrated setting of the arms 30 and 31 which support the contactbridges 25 and 26, the contact bridges engage their respective contacts substantially simultaneously. The engagement of contact bridge 25 with the contacts 34 and 35 completes a circuit from wire 137, through wire 146, contact 34, bridge 25, contact 35, actuating coil U75 of the up schedule relay, knife switch 126, to wire 138, for energizing the actuating coil U75 of the up schedule relay and thereupon causing the engagement of contacts U62 and U63. The up schedule relay is of the type that mechanically latches in after being operated, so that the contacts U62 and U63 are maintained in engagement after the deenergization of actuating coil U75 when the contact bridge 25 subsequently disengages from the stationary contacts 34 and 35. The engagement of contacts U62 is of no effect at the present moment, and their function will be described later. The engagement of contacts U63 completes a circuit from wire 137, through wire 147, knife switch 1--51, selector brush 1--44, selector contact 1-45, up start light 1-14, contacts 1LU68. actuating coil FU76 of the up flicker relay, contacts FU77 of the up flicker relay, contacts U63,

to wire 138, for causing the illumination of the up start light 1-l4 for car No. 1. The up start light is not steady in its illumination, however, as the energization of the actuating coil FU76 of the flicker relay results in the separation of con-' tacts FU77 to cause the breaking of the light circuit and the extinguishment oi the light. As soon as the light circuit is broken by the separation of the contacts FU77, the coil FU76 is deenergized so that the contacts F'U77 reengage, and thus the cycle repeats itself. In this manner the up flicker relay FU causes the up start light to flicker. The flickering up start light 1--14 is a signal to the operator oi the car No. 1 to leave the lower terminal floor. The engagement of contacts U63 also completes a circuit from wire 137, through wire 147, starters light 17 for the lower terminal floor, contacts FU77, contacts U63, to wire 138, for causing the illumination of the starters light 17. The contacts FU77 of the up flicker relay being included in this circuit, the starters light 17 flickers with the up start light 1-14. The flickering starters light 17 is a signal to the starter that a car at the lower terminal floor has received a signal to start.

The engagement of contact bridge 26 with the contacts 36 and 37 completes a circuit from wire 137, through wire 146, contact 36, bridge 26, contact 37, contact 133, blade 131 of the knife switch 130, actuating coil D80 of the down schedule relay, knife switch 125, to wire 138, for energizing the actuating coil D80 of the down schedule relay and thereupon causing the engagement of contacts D60 and D61. The down schedule relay is of the type that mechanically latches in after being operated so that the contacts D60 and D61 are maintained in engagement after the deenergization of actuating coil D80 when the contact bridge 26 subsequently disengages from the stationary contacts 36 and 37. The engagement of contacts D60 is of no eifect at the present moment, and their function will be described later. The engagement of contacts D61 completes a circuit from wire 137, through wire 147, kniie switch 3-51, selector brush 3-44, selector contact 3-46, down start light 3-15, contacts 3LD74, actuating coil FD81 of the down flicker relay, contacts F'D82 of the down flicker relay, contacts D61, to wire 138, for causing the illumination of the down start light 3-15 for car No. 3. The down start light is not steady in its illumination, however, as the energization of the actuating coil FD81 of the flicker relay results in the separation of contacts FD82 to cause the breaking of the light circuit and the extinguishment of the light. As-soon as the light circuit is broken by the separation of contacts F082, the coil FD81 is deenergized so that the contacts FD82 reengage, and thus the cycle repeats itself. In this manner, the down flicker relay FD causes the down start light to flicker. The flickering down start light 3-15 is a signal to the operator of car No. 3 to leave the upper terminal floor. The engagement of contacts D61 also completes a circuit from wire 137, through wire 147, starters light 18 for the upper terminal floor, contacts FD82, contacts D61, to wire 138, for causing the illumination of the starters light 18. The contacts FD82 o! the down flicker relay being included in this circuit, the starters light 18 flickers with the down start light 315. The flickering illumination 01' the starters light 18 is a signal to the starter that a car at the upper terminal floor has received a signal to start.

Assume that in compliance with the signal given by the up start light 114, the operator of car No. 1 closes the car and hatchway doors and starts his car upward. The movement of the car away from the lower terminal floor results in the upward movement of the selector brush 1-44. The roller 106 of the selector brush 1-44 engages the underside of the projecting end of the lower arm 1-47 with the result that as the car moves away from the lower terminal floor the lever arm is rotated so that the other end of the lever arm engages with the contact 1--48. A circuit is thereby completed from wire 137, through wire 147, knife switch 1--51, selector brush 1-44, lever arm 1-47, contact 148, reset coil U83, wire 153, contacts U63 to wire 138 for energizing the reset coil U83. As a result the mechanical latch 01 the up schedule relay U is released so that the relay drops back to its initial position with its contacts U62 and U63 disengaged. The purpose of the disengagement of contacts U62 will be explained later. The disengagement of the contacts U63 extinguishes both the up start light 114 and the starters light 17. The extinguishment of the starters light 17 is a signal to the starter that the car which received the up start signal to start has left the lower terminal floor.

The roller 106 of the selector brush 1-44 rides around the projecting end of the lever arm 147 as the car continues its motion away from the lower terminal floor and then the roller diengages from the lever arm. As a result the circuit for the actuating coil 1--LU64 is broken, 'so that the selective up light relay 1LU drops back to its initial position with its contacts 1LU65 and 1--LU66 in engagement, and its contacts 1LU67 and 1LU68 separated. The lever arm 1-47 returns to its initial position under the action of spring 120.

Assume that in compliance with the signal given by the down start light 3-15, the operator of car No. 3 closes the car and hatchway doors and starts his car downward. The movement of the car away from the upper terminal floor results in the downward movement of the selector brush 344. The roller 106 of the selector brush 3-44 engages with the underside of the projectin: end of the lever arm 3-49 with the result that, as the car moves away from the upper terminal floor, the lever arm is rotated so that the other end of the lever arm engages with the contact 3-50. The circuit is thereby completed from wire 137, through wire 14?, knife switch 351, selector brush 344, lever arm 349, contact 350, reset coil D84, wire 154, contacts D61, to wire 138, for energizing. the reset coil D84. As a result, the mechanical latch of the down schedule relay D is released so that the relay drops back to its initial position with its contacts D60 and D61 disengaged. The purpose of the disengagement of contacts D60 will be explained later. The disengagement of the contacts D61 extinguishes both the down start light 3-15 and the starters light 18. The extinguishment of'the starters light 18 is a signal to the starter that the car which received the down start signal has leftthe upper terminal floor.

The roller 106 of the selector brush 344 rides around the projecting end of the lever arm 349 as the car continues its motion away from the upper terminal floor and then the roller disengages from the lever arm. As a result, the circuit for the actuating coil 3-LD70 is broken so that the selective down light relay 3LD drops back to its initial position with its contacts 3- LD71 and 3LD72 in engagement and its contacts 3LD'73 and 3LD74 separated. The lever armv 349 returns to its initial position under the action of spring 120.

The timing motor continues to run and thus to cause the rotation of shaft 22 as indicated by the arrows. It is to be noted that with the angular spacing of the mounting arms 30, 31, and 32 illustrated in the drawings, soon after the disengagement of contact bridge from stationary contacts 34 and 35 and of contact bridge 26 from stationary contacts 36 and 37, contact bridge 27 engages with stationary contacts 42 and 43. This event is of no effect under the assumed conditions of operations, however, for the section of circuit which is completed by the bridge 2'7 terminates at the unengaged contact 136 of the knife switch 130. Subsequently, and after the shaft 22 has rotated one half of a revolution from the position in which bridge 26 was in engagement with contacts 36 and 37-, the bridge 26 engages the stationary contacts 38 and 39. This event is also of no eifect under the assumed conditions of operations, however, for the section of circuit completed by the bridge 26 termihates at the unengaged contact 135 of the knife switch 130. Soon after bridge 26 disengages from the contacts 38 and 39, the bridge 27 engages with the stationary contacts 40 and 41. This event is also of no effect, however, for the'secafter one revolution of the shaft 22. Before such -from the upper terminal floor.

reengagement, however, assume that car No. 2 arrives at the lower terminal floor and that car No. 4 arrives at the upper terminal floor. A sequence of operations similar to that previously described for car No. 1, transpires for car .No. 2 upon its arrival at the lower terminal floor. It is believed sufficient to point out that when car No. 2 is at the lower terminal floor level the actuating coil 2LU64 of the selective up light relay for car No. 2 is energized, contacts 2'LU65 and 2LU66 are disengaged and contacts 2-s-LU67 and 2-LU68 are engaged. A sequence of operations similar to that previously described for car No. 3 transpires for car No. 4 upon its arrival at the upper terminal floor. It is believed suflicient to point out that when car No. 4 is at the upper terminal floor level the actuating coil 4--LD70 of the selective down light relay for car No. 4 is energized, contacts 4LD71 and 4LD72 are disengaged, and contacts 4-LD73 and 4-LD74 are engaged. Accordingly, when the contact bridge 25 now engages with the stationary contacts 34 and 35, the actuating coil U of the up dispatching relay is again energized, andits contacts U62 and U63 reengage. The reengagement of the contacts U62 under the present assumed conditions of operation is, as before, of no effect. The engagement of contacts U63 completes a circuit for the up start light 214 similar to that previously described for the up start light 1-14, and also completes the. circuit for the starters light 17. The up start light 214 and the starters light 1'7 are thereupon both illuminated, and are caused to flicker by the operation of the up flicker relay FU. The flickering up start light 2--14 is a signal to the operator of car No. 2 to leave the lower terminal floor while the flickering starters light 17 is a signal to the starter that a car at the lower terminal floor has received a signal to start. bridge 26 engages with the stationary contacts j 36 and 37, which, with the illustrated setting of actuating coil D8601 the down dispatching relay I is again energized and its contacts D60 and D61 reengage. The reengagement of the contacts D60 under the present assumed conditions of operation is, as before, of no effect. The engagement of contacts D61 completes a circuit for the down start light 4-15 similar to that previously described for the downstart light 315, and also completes the circuit for the starters light 18. The down start light. 415 and the starters light 18 are thereupon both illuminated, and are caused to flicker by the operation of the down flicker relay FD. The flickering down start light 4-15 is asignal to the operator of car No. 4 to leave the upper terminal floor, while the flickering starters light 18 is a signal to-the starter that a car at the upper terminal floor has received a signal to start.

Assume now thatv incompliance with the signal given by the up start light 2-14, the operator of car No. 2 starts his car upward from the lower terminal floor, and that in compliance with the signal given by the down start light 4--15, the operator of car No. 4 starts his car downward In a manner similar to that previously described for the dep'arture of car No. 1 from the lower terminal floor,

the departure of car No. 2 from the lower terminal floor resets the up schedule relay U, extinguishes the up start light 2--14 and the starters light 17, and deenergizes the actuating coil When the contact of the selective up light relay 2-LU to permit the contacts thereof to'return to their initial positions. In a manner similar to that previously described for the departure of car No. 3 from the upper terminal floor, the departure of car No. 4 from the upper terminal floor resets the down schedule relay D, extinguishes the down start light 4-15 and the starters light 18, and deenergizes the actuating coil of the selective down light relay 4-LD to permit the contacts thereof to return to their initial positions.

The timing motor continues to run, and, under the conditions'of operation that have been assumed, the previously described cycle of events after the disengagement of contact bridge 25 from the stationary contacts 34 and 35 and contact bridge 26 from stationary contacts 36 and 37 to the reengagement of these bridges with their respective stationary contacts again transpires.

It is assumed, similarly as has been previously assumed, that before the reengagement of contact bridge 25 with the stationary contacts 34 and 35 and the reengagement of contact bridge 26 with the stationary contacts 36 and 37, a car has arrived at the lower terminal floor and another car has arrived at the upper terminal floor. Under normal operating conditions, car No. 3 would be the car to have arrived at this time at the lower terminal floor and car No. 1 at the upper terminal floor. Accordingly, it is so assumed. There transpires for car No. 3 a cycle of events similar to that previously described while car No. 1 was at the lower terminal floor and there transpires for car No. 1 a cycle of events similar to that previously described while car No. 3 was at the upper terminal floor.

Further description of the operation of the system under conditions, similar to those that have been assumed is believed unnecessary. It is believed clear that when a car at each terminal floor is started away with reasonable promptness in compliance with the corresponding up start or down start signal given it, and that before the expiration of the normal time interval after the giving of that start signal (as determined by a complete, continuous revolution of the shaft 22) a car again arrives at each terminal floor, the start signals are given without delay at the expiration of the normal time interval. Under these conditions the start signals are given at regular intervals, and thus there is regularity in the dispatching of he cars from both terminal floors. The elevator service thus tends to be uniform, for there is normally the same number of cars on the up trip as on the down trip. This relationship among the cars may be termed as having the cars balanced.

It may happen, for example, when a car makes more than a normal number of stops during a trip, or when it is delayed for other causes, that the car has not arrived at the terminal floor by the time that it is scheduled to depart therefrom. For example, assume, that car No. 1 has been delayed in its travel toward the lower terminal floor. The engagement of contact bridge 25 with the stationary contacts 34 and 35 before the arrival of car No. 1 at the lower terminal floor completes a circuit for the actuating coil U75 of the up schedule relay similarly as previously described.

The resulting operation of the up schedule relay U causes the engagement of its contacts U62 and U63, and the mechanical latching in of the relay to maintain these contacts in engagement; The engagement of contacts U82 is of no effect at the present moment. The engagement of contacts U63 completes a circuit for the starter's light 17 from wire 137, through wire 147, starter's light 17 for the lower terminal floor, contacts FU77, contacts U63, to wire 138, for causing the illumination of the starter's light 17. As the car is not at the lower terminal floor, with the result that its selector brush 1-44 is not in engagement with the lower terminal floor selector contact 1-45, the engagement of contacts U63 does not cause the illumination of up start light 1-14 or cause the operation of the up flicker relay EU. The contacts FU77 of the up flicker relay thus remain in engagement, so that the circuit to the starters light 17 is uninterrupted. The resulting steady illumination of the starter's light 17 is a signal to the starter that a starting signal is being given to dispatch a car from the lower terminal floor, and that nocar eligible to be dispatched in response thereto has arrived at that floor.

When car No. l arrives at the lower terminal floor and its selector brush 1-44 engages with the'projecting end of the lever arm 1-47, the actuating coil of the selective up light relay l-LU is energized to cause and maintain, among other things, the engagement of its contacts 1-LU68. The details by which this is efiected has been previously described. The circuit for the up start light 1-14 is'thereby completed. This circuit has also been previously traced. Inasmuch as the actuating coil FU76 of the up flicker relay is energized along with the up start light 1-14, the up flicker relay operates. The resulting engagement, separation and reengagement of the contacts FU77 causes both the up start light 1-14 and the starters light 17 to flicker. This condition continues while the car remains at the lower terminal floor, it being remembered that the selective up light relay l-LU is maintained operated while the selector brush 1-44 engages the lower terminal floor selector contact 1-45. The flickering up start light 1-14 is the signal to the operator of car No. 1 to leave the lower terminal floor. The change in the illumination of the starter's light 17 from a steady to a flickering light is a signal to the starter that a car eligible to be dispatched has arrived at the lower terminal floor and that that car is receiving the dispatch signal to start. Both lights continue to operate in a flickering fashion until, as previously described, they are extinguished upon the departure of the car from the lower terminal floor.

A similar operation occurs in the event that a car is delayed. in reaching the upper terminal floor. bridge 26 engages with stationary contacts 36 and 37 before the arrival of car No. 3 at the upper terminal floor, a circuit is completed for the actuating coil D80 of the down schedule relay D similarly as previously described. The resulting operation of this relay causes the engagement of its contact D60 and D61 and the mechanical latching in of the relay to maintain these contacts'in engagement. The engagement of contacts D60 is of no effect at the present moment. The engagement of contacts D61 completes a circuit for the starter's light18 from wire 137, through wire 147, starter's light 18, contacts FD82, contacts D61, to wire 138, for causing the illumination of the starter's light 18. As car No. 3 is not at the upper terminal floor, with the result that its selector brush 3-44 is not in- Assuming. for example, that the contact,

' D61 does not cause the illumination of down start light 3-15 or cause the operation of the down flicker relay FD. The contacts F1382 of the down flicker relay thus remain in engagement, so that the circuit to the starter's light is uninterrupted. The resulting steady illumination of the starters light 18 is a signal to the starter that a starting signal is being given to dispatch a car from the upper terminal floor, and that no car eligible to be dispatched in response thereto has arrived at that floor.

When car No. 3 arrives at the upper terminal floor and its selector brush 3-44 engages with the projecting end of the lever arm 3-49, the actuating coil of the selective down light relay 3-LD is energized to cause and maintain, among other things, the engagement of contacts 3-LD74. The details by which this is effected have been previously described. The circuit for the down start light 3-l5 is thereby completed. This circuit has also been previously traced. Inasmuch as the actuating coil FD81 of the down flicker relay is energized along with the down start light 3-15, the down flicker relay operates. The resulting engagement, separation, and reengagement of the contacts FDBZ causes both the down start light 3-15 and the starters light 18 to flicker. This condition continues while the car remains at the upper terminal floor, it being remembered that the selective downlight relay 3-LD is maintained operated while the selector brush 3-44 engages the upper terminal floor selector contact 3-46. The flickering down start light 3-15 is the signal to the operator of car No. 3 to leave the upper terminal floor. The change in the illumination of the starters light 18 from a steady to a flickering light is a signal to the starter that a car eligible to be dispatched has arrived at the upper terminal floor and that that car is receiving the dispatch signal to start.

Both lights continue to operate in a flickering fashion until, as previously described, they are extinguished upon the departure of the car from the upper terminal floor.

The above described operation of the starters lights 1'? and 18 assists the starter or other ofllc'ial in the complete supervision of the bank of elevators. He is informed when a dispatch sigml is given'by the scheduling device. He is informed whether or not there is a car eligible to receive this dispatch signal at the terminal floor for which the signal is given, and if there is no car eligible to receive this dispatch signal at the terminal floor, when such a car does arrive at the terminal floor. He is informed all during the time a car is receiving a dispatch signal. He is also informed when the car actually leaves in response to such signal. Thus he may see whether or not the operators are starting their cars away from the terminal floors with reasonable promptness after they have received the signal to start. In the system illustrated this supervision extends to both the lower and upper terminal floors. Utilization" of the system inconjunction with the indicators that show the positions of the cars in the elevator bank enables the starter to determine which of the cars V lighter than normal. In this event the succeeding car may overtake and pass the preceding car timing mechanism.

and be the prior of the two to arrive at the terminal floor destination. When this situation occurs, the car first arriving and causing the other cars, and the operation of the selective down light relay LD for the car first to arrive at the upper terminal floor causes the separation of its corresponding back contacts LD'll and 1.11372 to prevent the operation of the selective down light relay for each of the other cars. Accordingly, should the overtaken car arrive at the terminal floor before the overtaking car receives the dispatch signal to start, the overtaken car does not receive that dispatch signal. Only after the overtaking car has left the terminal floor, and in so doing has reset the schedule relay U or D and deenergized its corresponding selective up or down light relay, and after the selective up or down light relay for the overtaken car operates, is the overtaken car able to receive a dispatch signal to start. The overtaken car is then dispatched by the next succeeding dispatch signal. Thus the dispatch signal which the overtaken car receives is the next succeeding dispatch signal that is given for that terminal floor by the As a result of the above described operations that occur when a car is overtaken by a succeeding car, the succeeding car is moved up into the place of the overtaken car in the system, and the overtaking car is dropped -With the arrangement of the cars and the system that has been previously described, assume that car No. 1 has been delayed in its travel toward the lower terminal floor while car No. 3 has arrived at the upper terminal floor substantially according to schedule, and departs therefrom promptly upon receipt of the starting signal. As

a result, the cycle of events with regard to the delayed car only, car No. 1, need be described. The engagement of contact bridge 25 with the stationary contacts 34 and 35 before the arrival of car No. 1 at the lower terminal floor causes the operation of the up schedule relay U, the engagement and latching-in of contacts U62 and U63, and the illumination of the starter's light 1'7, all as previously explained. The contact bridge 25 then disengages from contacts 34 and 35 and,

with the setting of the arms 30and 32 that is illustrated in the drawings,'soon thereafter contactbridge 27 engages with the stationary contacts 42 and 43. This event is of no effect, under the assumed conditions of operation wherein the knife switch .130 is thrown to the left, for the section of circuit which is completed by the contact bridge 2'1 terminates at the unengaged contact 136 of this knife switch 130. After the disengagement of contact bridge 27 from contacts 42 and 43, substantially one-half of a revolution of timing shaft 22 ensues before bridge 27 engages with the contacts 40 and 41. Under normal operating conditions for the arrangement of the cars and the adjustment of the system that have been assumed, and allowing for average temporary delays, car No. 1 should depart from the lower terminal floor before contact bridge 27 engages with contacts 40 and 41. In the event that the car has not departed when bridge 27 engages with contacts 40 and 41 (which condition may result when the car has not yet arrived at the lower terminal floor as well as when the car has arrived at the lower terminal floor but not departed therefrom) the engagement of bridge 27 with contacts 40 and 41 completes a circuit for energizing the actuating coil K78 of the timing motor relay. This circuit may be traced from wire 137, through contacts U'U57, contacts U62, stationary contact 40, contact bridge 27, stationary contact 41, actuating coil K78, to wire 138. (It is recalled that knife switch 126 is closed so that the up dispatching relay UU is operated to maintain contacts UU57 in engagement.) lhe resulting operation of the timing motor relay causes the separation of its contacts K52 in the timing motor feed. Accordingly, the timing motor 20 stops and the timing shaft 22 ceases to revolve. The timing is thus suspended pending the departure of the car from the lower terminal floor. This suspension aids in the readjustment of the system to the excessive delaying of car No. 1, and tends to keep the cars in the desired balanced relation. This is hereinafter more fully described. When car No. 1 eventually does depart from the lower terminal floor, its departure results in the resetting of the up schedule relay U, and thus in the restoration of contacts U62 to their initial disengaged condition. The manner by which this is effected has been previously described. The separation of contacts U62 breaks the circuit for the actuating coil K78 of the timing motor relay, and so permits the reengagement of its normally engaged contacts K52 to cause the reenergization of timing motor 20. The timing motor thereupon resumes its operation to cause the rotation of timing shaft 22, and thus to resume the normal oper-- ations of the system.

Assume the condition reverse to that above, wherein with the arrangement of the cars and the system as has been previously described, car No. 3 has been delayed in its travel toward the upper terminal floor, while car No. 1 has arrived at the lower terminal floor substantially according to schedule and departs therefrom promptly upon receipt of the starting signal. As a result, the cycle of events with regard to the delayed car only, car No. 3, need be described. The engagement of contact bridge 26 with the stationary contacts 36 and 37 before the arrival of car No. 3 at the upper terminal floor causes the operation of the down schedule relay D, the engagement and latching-in of contacts D60 and D61, and the illumination of the starters light 18, all as previously explained. The contact bridge 26 then disengages from contacts 36 and 37, and ,with the setting of the arms 31 and 32 that is illustrated in the drawings, soon thereafter contact bridge 27 engages with the stationary contacts 42 and 43. This event is of no effect under the assumed conditions of operation wherein the knife switch 130 is thrown to the left, for the section of circuit which is completed by the contact bridge 27 terminates at the unengaged contact 136 of this knife switch 130. After the disengagement of contact bridge 27 from contacts 42 and 43, substantially one-half of a revolution of timing shaft 22 ensues before bridge 27 engages with the contacts 40 and 41. During the course of this onehalf of a revolution contact bridge 26 engages with, and separates from, the contacts 38 and 39. This event is of no effect, however, for the section of circuit completed by the bridge 26 terminates at the unengaged contact 135 of the knife switch 130. Under normal operating conditions for the arrangement of the cars and the adjustment of the system that have been assumed, and allowing for average temporary delays, car No. 3 should depart from the upper terminal floor before contact bridge 27 engages with contacts 40 and 41. In the event that the car has not departed when bridge 27 engages with contacts 40 and 41 (which condition may result when the car has not yet arrived at the upper terminal floor as well as when the car has arrived at the upper terminal floor but not departed therefrom), the engagement of bridge 27 with contacts 40 and 41 completes a circuit for energizing the actuating coil K78 of the timing motor relay. This circuit may be traced from wire 137 through contacts DD55, contacts D60, blade 132 of knife switch 130, contact 132, stationary contact 40, contact bridge 27, stationary contact 41, actuating coil K78, to wire 138. (It is recalled that knife switch 125 is closed so that the down dispatching relay DD is operated to maintain contacts DD55 in engagement). The resulting operation of the timing motor relay causes the separation of its contacts K52 in the timing, motor feed. Accordingly, the timing motor 20 stops and the timing shaft 22 ceases to revolve. The timing is thus I suspended pending the departure of the car from the upper terminal floor. This suspension aids the readjustment of the system to the excessive delaying of car No. 3 and tends to'keep the cars in the desired balanced relation. This is hereinafter more fully described. When car No. 3 eventually does depart from the upper terminal floor its departure results in the resetting of the down schedule relay D, and thus in the restoration of contacts D60 to their initial disengaged condition. The manner by which this is eii'ected has been previously described. The separation of contacts D60 breaks the circuit for the actuating coil K78 of the timing motor relay and so permits the reengagement of its normally engaged contacts K52 to cause the reenergization of the timing motor 20. The timing motor thereupon resumes its operation to cause the rotation of timing shaft 22, and thus to resume the normal operations of the system.

It was assumed for the above described suspension of operation of the timing motor, first, that there was a delay in the departure of a car from the lower terminal floor only, then secondly, that there was a delay in the departure of a car from the upper terminal floor only. It may happen, however, that there may be a delay in the departure of one car from one terminal floor while there is a delay in the departure of another .car from the other terminal floor. Under such a condition, the timing may be suspended as a retacts UU57 and U62, and on the other, by way of contacts DD55 and D60. Hence the timing motor relay K is maintained operated to keep the timing motor deenergized until both contacts U62 and D60 are caused to separate. This occurs, as previously explained, as a result of the departure of a car from each floor in response to the signals to start therefrom.

It is believed to be clear from all the foregoing that, with the assumed operating conditions, the suspension of operation of the timing motor may be effected as a result of the delayed departure of each car from the lower terminal floor in a manner similar to that just described for car No. l, and of each car from the upper terminal floor in a manner similar to that just described for car No. 3. Thus, under the assumed conditions of operation, if any car is excessively delayed and is not overtaken by a succeeding car, with the result. that no car departs from the terminal floor by a definite time interval after the time scheduled for a car to depart from that terminal floor, (which condition may result when the car has not yet arrived at the terminal floor as well as when the car has arrived at the terminal floor but not departed therefrom), the system automatically suspends timing operations. The timing operations are resumed after a car has departed from the terminal floor in response to the dispatch signal to "which no car had responded at the time the timing operations were suspended. It may be noted at this point that in the event that at the time the timing operations were suspended no car had arrived at the terminal floor, the dispatch signal to start is given to the first car to arrive at the terminal floor. This car may be the delayed car, or, if the delayed car is overtaken by a succeeding car, it may be such succeeding car. At any event, the timing operations are resumed only upon the departure of a car in response to the dispatch signal. Under these conditions the system operates to automatically adjust itself to an overdelayed departure of a car and thus tends to maintain the balanced relation among the cars.

The situation presented by the preceding paragraph may be briefly outlined with reference to Figure 1. As therein shown, the cars are substantially evenly spaced in a figurative traffic loop extending from the lower terminal floor, up to the upper terminal floor, and back again to the lower terminal floor. With four cars included in the dispatching system, two cars are operating on the up port-ion of the traffic loop,

and two cars on the down portion of the trafllc- I floor by the definite time interval after the time ing laid'for possible subsequent unbalanced operation oi the system. For example, if the timing should continue and a full scheduling interval should elapse after the time the schedule relay forthat terminal floor had operated and no car should depart from that terminal floor during that interval, there would then be during that interval at that terminal floor no transfer of a car from the portion of the traffic loop leading to that terminal floor, to the portion of the traffic loop leading away therefrom. Thus, there would then be three cars on one portion of the traflic loop (operating downwardly, for example) and only one car on the other portion of the traflic loop (operating upwardly, for example). When a car should then leave the terminal floor after the first full scheduling interval had elapsed, and thus, after a second scheduling interval had been started, the departure of the car would reset the schedule relay, with the result that the starting signal to the next car would depend upon the initiation of a succeeding scheduling interval. Accordingly, the opportunity is lost for dispatching a car for the interval during which no car departed. As a result the intervention of the starter would ordinarily be necessary in order to brin'g the cars back into halanced relationship. By suspending the timing the knife switch 451 is opened. As an odd number of cars is now subject to the control of the system, the knife switch 130 is thrown to the right so that its blade 131 engages contact 135 and its blade 132 engages contact 136." This change is made so that the odd number of cars may be dispatched from the terminals in such a manner as to obtain a relationship among the odd number of cars that is analogous to the balanced relationship among an even number of It is clear that when an odd number of cars. cars is included in the system, it is not possible to have the number of cars operating on the down portion of the figurative traific loop equal to the number of cars operating on the up portion thereof. A relationship for an odd number of cars analogous to the balanced relationship for an even numberof cars is schematically illustrated in Figure 6. At the instant that car No. 1 is at the lower terminal floor 11 and receiving a dispatch signal to start, car No. 2 is in the upper portion of the hatchway on a down trip, and car No. 3 is in the upper portion of the hatchway on an up trip. The cars at this instant of time, which for convenience may be designated time No. l, are schematically shown in full-line outline. At a later instant of time, designated time No. 2, when car No. 3 is at the upper terminal floor 12 and receiving a dispatch signal to start, car No. 1 is in the lower portion of the hatchway on its up trip, and car No. 2 is in the lower portion of the hatchway on its down trip. The dotted outlines of the cars show their position at time No. 2. At a still later instant of time, designated time No, 3, car No. 2 is at the lower terminal floor receiving a dispatch signal to start, while car No. 1 is in the upper portion of the hatchway on its up trip and car No. 3 is in the upper portion of the hatchway on its down trip. The positions of the cars at this time No. 3 are not shown in Figure 6. From this analysis it may be seen that during the interval between the dispatch of a car from the lower terminal floor and the dispatch of the next succeedin r therefrom,

' itiation of the dispatch signal for a car at the upa car is dispatched from the upper terminal floor. This is effected, with knife switch 130 thrown over to the right, as mentioned above, in the following manner.

The dispatch signal for cars at the lower terminal floor is initiated upon the engagement of contact bridge 25 with stationary contacts 34 and 35 similarly as previously described. The engagement of contact bridge 26 with contacts 36 and 37 is of no effect as the circuit partially completed thereby is open at the unengaged contact 133. During the course of a revolution of the timing shaft 22 after the engagement of bridge 25 with contacts 34 and 35, the bridge 26 engages with contacts 38 and 39. This occurs, with the illustrated setting of the arms 30 and 31, in the neighborhood of half an interval after the engagement of bridge 25 with contacts 34 and 35. The engagement of bridge 26 with contacts 38 and 39 completes a circuit from wire 137, through wire 146, contact 38, bridge 26, contact 39, contact 135, blade 131 of knife switch 130, actuating coil D80 of the down schedule relay, to wire 138, for causing the operation of the down schedule relay and thus the inper terminal floor.

The throwing of knife switch 130 over to the right also adjusts the time-suspending function of the dispatching and scheduling system to the inclusion of an odd number of cars in the system. In the event, for example, that a car fails to leave the lower terminal floor during the interval between the engagement of bridge 25 with contacts 34 and 35 and-the engagement of bridge 27 with contacts 40 and 41, the timing motor relay K operates similarly as previously described to suspend timing operations. On the other hand, in the event that a car fails to leave the upper terminal floor during the interval between the engagement of bridge 26 with contacts 38 and 39 and the engagement of bridge 27 with contacts 42 and 43, the engagement of bridge 27 with contacts 42 and 43 causes the operation of the timing motor relay K to suspend timing operations in a similar manner. The circuit which is completed in the latter situation to cause the operation of the timing motor relay K may be traced from wire 137,

through contacts DD55, contacts D60, blade 132 of knife switch'130, contact 136, contact 42, bridge 27, contact 43, actuating coil K78 of the timing motor relay, to wire 138.

Accordingly, it is believed clear from the foregoing that any number of cars may be made subject to the control of the dispatching and scheduling system upon the closing of the knife switch 51 for each car to be included in the system, and the throwing of knife switch 130 to the left or right depending on whether the total number of cars included is even or odd.

During certain times of the day, as for example, in the morning, the passenger traflic may be predominately from the lower terminal floor up into the building. Under these circumstances it may be desirable to reduce to a minimum the period during which va. car may be at the upper terminal floor waiting for the expiration of the scheduling interval after the giving of the down dispatch signal to the preceding car. In such event the starter may open knife switch 125. As a result the actuating coil DD53 of the down dispatching relay is deenergized thereby effecting the engagement of its contacts DD56 and the separation of its contacts DD55. The engagement of contacts DD56 establishes a by-pass erates, the circuit through its down start light 15 is complete so that the car receives the down dispatch signal immediately. The separation of contacts DD55 renders the timing suspension function inoperative for the upper terminal floor so that, with the actuating coil D of the down schedule relay also inoperative as a result of the opening of knife switch 125, the continued rotation of timing shaft 22 is of no effect so far as the upper terminal floor is concerned.

During certain other times of the day, as for example, in the evening, the passenger traffic may be predominately from the upper floors of the building down to the lower terminal floor. Under these circumstances it may be desirable to reduce to a minimum the period during which a car may be at the lower terminal floor waiting for the expiration of the scheduling interval after the giving of the up dispatch signal to the preceding car. In such event the starter may open knife switch 126. As a result the actuating coil UU54 of the up dispatching relay is deenergized, thereby effecting the engagement of its contacts UU58 and the separation of its contacts UU57. The engagement of contacts UU58 establishes a by-pass circuit across the contacts U63 of the up schedule relay U so that the effect is the same as if these contacts of the up schedule-relay were maintained in engagement. Accordingly, as soon as a car arrives at the lower terminal floor and its selective up light relay LU operates, the circuit through its up start light 14 is complete so that the car receives the up dispatch signal immediately. The separation'of contacts UU57 renders the timing-suspension function inoperative for the lower terminal floor so that, with the actuating coil U75 of the up schedule relay also inoperative as a result of the opening of knife switch 126, the continued rotation of timing shaft 22 is of no effect so far as the lower terminal floor is concerned.

It is to be noted that in the event that the passenger traific becomes extremely heavy, the starter may dispense with the scheduled interval between cars at both terminal floors by opening both knife switch 125 and knife switch 126. As a result each car receives the signal to start as soon as it arrives at a terminal floor and its selective light relay for that floor operates. In this manner the cars may be operated to give maximum service during peak traffic conditions.

Under certain conditions of operation it may happen that at the time that a car leaves a terminal floor in compliance with a signal to is within the realm of possibility in a four car bank. For convenience, assume that when car No. 1 leaves thelower terminal floor, cars No. 2 and No. 3 remain at that terminal floor. The

departure of car No. 1 deenergizes the selective of this latter change is up light relay 1--LU so that contacts 1--LU66 engage. The engagement of contacts l-LU66 completes a circuit for the actuating coil 2-LU64 the value of the reactance X150; Each selective.

up light relay is designed to operate at a predetermined current flow which is different from that for which the other relays are set to operate. means, a simple one being a different air gap adjustment for each relay. Accordingly, as the current flow builds up, a value is reached suflicient to cause the operation of the selective up light relay for one car, for example, car No. 2, but as yet insufficient to cause the operation of that relay for the other car, car No. 3. As a result, the selective up light relay for car No. 2 operates, which immediately, due to the separation of its contacts 2-LU66, breaks the circuit for the actuating coil of the selective light relay for all other cars, including that for car No. 3. Hence only one car of those remaining at the time car No. l departed is made eligible to receive the next dispatch signal. In this manner only one car is ever dispatched at a time fronrthe lower terminal floor. By a similar process, for briefness not detailed, only one car is ever dispatched at a time from the upper terminal floor,

In the event that no cars are at a terminal floor, the car first to arrive and cause the operation of its selective light relay for that terminalfloor is the car first to receive a dispatch signal. This is due to the fact, previously described, that the op: eration of the selective light relay for a car breaks the circuit for the actuating coils of the selective light relays for that terminal floor for all the other cars. As a result any car that arrives subsequent thereto and before the first car has departed, does not receive the dispatch signal that is given to the first car.

It is to be noted that the scheduling interval may be lengthened or shortened by the adjustment of the speed control switch 142. This switch, as previously explained, regulates the speed with which the timing motor 20 runs, and thus the speed with which the timing shaft 22 rotates.

It is also to be noted that the arms 30, 31 and 22 so as to increase or decrease the predetermined time after the operation of a schedule relay before the timing is suspended, in the event that no car has departed during that time. In addition, the arms 30 and 31 may be set with an appreciable angular relationship between them. The effect to vary the relationship between the time allowed for an up trip and the time allowed for a down trip. In other words, the arms 30 and 31 may be adjusted so that the time consumed for a round trip may be apportioned in varying amounts to the up trip and to the down trip. This adjustment may be made to facilitate the operation of the scheduling system to the conditions of a particular building or of a particular period of time. In explanation of the manner by which the varying relationship between the up time and the down time is effected, assume for example, that the arm 31 is reasonably set back from the arm 30 The result- This may be effected by a variety of official in addition to the other equipment ing angular relationship between arms 30 and 31 may, for convenience, be designated by the setback angle A. Consider an instant when arm 30 is in the position to dispatch a car from the lower terminal floor as the instant from which subsequent time is computed, and assume, for the moment, that only two cars, cars Nos. 1 and 3, are

included in the dispatching system. At the starting time, therefore, car No. l is dispatched from the lower terminal floor. Subsequently, by the time represented by the set-back angle A, car No. 3 is dispatched from the upper terminal floor. After the time from the starting instant represented by one revolution of timing shaft 22, arm

30 is again in the position to dispatch a car from the lower terminal floor. At this time car No. 3 is dispatched therefrom. Subsequently, by the time represented by the set back angle A, or in other words, measuring from the starting instant, at the time represented by 360 degrees (one revolution) plus the set-back angle A, arm 31is in the position to dispatch a car from the upper terminal floor, and accordingly, car No. 1 is dispatched therefrom. At a still later time, when arm 30 is next in position to dispatch a carfrom the lower terminal floor, (which event, measuring from the starting instant, is at the time represented by two revolutions of the timing shaft or 720 degrees) car No. 1 is again dispatched from the lower terminal floor. Accordingly, the round trip time, represented by 720 degrees or two revolutions of the timing shaft 22, is apportioned so that the up trip time is represented by 360 degrees (one revolution) plus the set-back angle A, and the down trip time is represented by 360 degrees (one revolution) minus the set-back angle A. When an even number of cars greater than two is included in the dispatching system, the operation is similar to that described above for two cars, except that, if the same service is to be given in each case, a round trip time for a. .car may be greater by a proportionate number of complete revolutions of timing shaft 122 Accordingly, the up time and the down time are correspondingly greateralthough their difference, (represented by twice the set-back angle, or 2A) is the same. When an odd number of cars is included in the dispatching system it may be seen that the operation is fundamentally analogous to that above described so accordingly it is not set forth.

From the above outline of the effects attendant upon adjusting the arms 30, 31 and 32 upon the timing shaft, it may be desirable, under certain conditions, to have their adjustment readily subject to the control of the starter or other supervising oflicial. In such event the timing shaft 22,

with its associated contacts, driving motor and starter or such other which may be readily accessible to such oflicial. If desired, each arm may be connected, through the medium of a hollow shaft, for example, to a corresponding arm positioned on the exterior of a suitable panel. The timing shaft may also be arranged to extend through the panel, and be provided with suitable means to lock the exterior arms thereto, as for example, a locking nut. With such an arrangement the setting of the arms may be readily subject toadjustment.

Attention is directed to the tion has been made so far in regard to lights over the hatchway doors at the terminal floors. In

veniently accessible to the some buildings such lights are not provided.

of the cars is at the terminal floor preparatory to departing therefrom, it may be desirable to have each of such lights dependent upon the operation of the selective up or down light relay, as the case may be, for the corresponding car.

-This may be effected by providing an extra set of forward contacts on the selective up or down light relay for each car, and arranging such extra contacts for each car in the appropriate terminal floor hall light circuit of the corresponding car. With such an arrangement, in the event that two or more cars are at the terminal floor at the same time, only the terminal floor hall light for the car that has effected the operation of its selective light relay, and so for the car first to receive the next dispatch signal, is lighted. It may also be desirable to notify the operator within a car at a terminal floor that his car is the next one to be dispatched, and that passengers are being directed to his'car. In such event a notification light for that terminal floor may be mounted within each car, and connected in parallel with the hall light at that terminal floor for the corresponding car. As a result of this arrangement the notification light for each car is lightedat the same timethat the terminal floor hall light is lighted. For simplicity, such hall lights and notification lights have been omitted in the diagram of Figure 2.

Figures 7 and 8 taken together constitute a wiring diagram of a dispatching and scheduling system that embodies certain features in addition to those embodied in the system as described with reference to the diagram of Figure 2. For ease in the understanding of Figures 7 and 8, and to avoid a description of the operation thereof which would be partially repetitious of the description of operation of Figure 2, the apparatus in Figures 7 and 8 corresponding to apparatus in Figure 2 and operating in a manner similar thereto, is designated similarly as in Figure 2. Such apparatus includes the car starting lights 14 and 15 and the starters lights 17 and 18; the timing motor 20 and its associated circuits and apparatus; the timing shaft 22, the contact bridges 25, 26 and 27 fastened thereto, the stationary contacts engaged by said contact bridges, and the circuits, switches and relays associated with said stationary contacts; the floor selector brushes; the selective light relays, the flicker relays, and the circuits and other apparatus associated therewith. In addition, the position in which such apparatus is shown in Figures 7 and 8 corresponds withthe position in which such apparatus is shown in Figure 2. As a result, the preceding description of the operation of the system of Figure 2 is applicable to the system of Figures 7 and 8, with such additions and changes as are hereinafter described.

The floor selector contacts employed in the system of Figures 7 and 8 are preferably a slightly modified form of the selector contact employed in the system of Figure 2 5. This floor selector contact preferably employed in the system in Figures 7 and 8 is shown in Figure 9. It is similar in construction to the selector contact shown in Figure 5 except for the lever arm 47. The lever arm of the selector contact shown in Figure 9, designated 187, is formed of insulating material. Its projecting end is provided with a metallic tip 188 which is secured thereto, as by a rivet 190. The other end of the lever arm 187 is provided with a contact 191 arranged to engage with the contact 48 when the lever arm 187 is rotated out of its normal posiand illustrated in Figure tion. The contact 191 is mounted upon the lever arm 187 as by the rivet 192. An electrical connection 194 is provided to connect the metallic tip 188 with the contact 191. Insulating bushing 198 is provided for the rivet 190 so as to insulate it from the metallic tip 188 and the connection 194. As a result of this construction, the engagement of the selector brush 44 for a car with the metallic tip 188 on the lever arm 187 as such car arrives at the terminal floor for which such selector contact of Figure 9 is provided, is without effect, since the tip 188 is insulated from the member 115 and lip 116. When the car departs from such terminal floor, the selector brush 44 for such car causes the rotation of the lever arm 187 in the manner analogous to that eiTected for the lever arm 47 0f the selector contact of Figure 5. However, before contact 191 upon the lever arm 187 engages with the contact 48, the selector brush-44 disengages from the contact lip 116. As a result, at the time a circuit is completed from the selector brush 44, by way of tip 188, connector 194, contact 191, to contact 48 there is no circuit from the selector brush 44 to the member 115. The effect of such modifications in the selector contact upon the operation of the dispatching and scheduling systems will become clear from the description of operation of the system of Figures 7 and 8 which follows later.

Apparatus in Figures 7 and 8 that is additional to that shown in Figure 2 includes for each car a selector brush 160, a lower terminal floor selector contact 161, and an upper terminal floor selector contact 162. The selector brush 160 for each car is arranged so that it engages with the lower terminal floor selector contact for that car when that car is at the lower terminal floor, and so that it engages with the upper terminal floor selector contact for that car when that car is at the upper terminal floor. The selector brush 160 may be similar in construction to the selector brush 44. The terminal floor selector contacts 161 and 162 may be simple contact lips similar in construction to the contact lip 116. Placed in a connection between the wire 147 (connected to the positive main) and the selector brush 160 for each car is a knife switch 163. The closing of knife switch 163 for each car serves to render the selector brush 160 for that car alive. If desired, the knife switches 51 and 163 for each car may be arranged so that they may be operated simultaneously, due to the fact, as will be seen as the description proceeds, that these two knife switches are ordinarily opened and closed together.

From the lower terminal floor selector contact 161 for each car there is a circuit through an auxiliary set of contacts LU90.of the selective up light relay LU for the corresponding car, and through a. hall light 164 at the lower terminal floor for the corresponding car, to the wire 138 (connected to the negative main). As a result of this arrangement, whenever a car is at the lower terminal floor and the selective up light relay for that car is operated, the circuit for the lower terminal floor hall light for that car is complete, and that hall light is illuminated. The circuit thatis completed, assuming, for illustration, that car No. 1 is at the lower terminal floor and that selective up light relay 1LU has operated, may be traced from wire 137, through wire 147, knife switch 1163, selector brush 1160, lower terminal floor selector contact 1161, lower terminal floor hall light 1-164, contacts 1LU90 of the selective up light relay, to wire 138. As

was described with reference to the system of Figure 2, when the selective up light relay for a car operates, that car is the car that next receives the signal to start. Accordingly, the lower terminal floor hall light for a car is illuminated only,when that car is the next one to be dispatched. Thus, in the event that there should be more than one car at the lower terminal floor, prospective passengers are directed to the proper car.

From the upper terminal floor selector contact 162 for each car there is a circuit through an auxiliary set of contacts LD91 of the selective down light relay ID for the corresponding car, and througha hall light 165 at the upper terminal floor for the corresponding car, to the wire 138 (connected to the negative main). As a result or! this arrangement whenever a car is at the upper terminal floor and the selective down light relay for that car is oper ted, the circuit for the upper terminal floor hall light for that car is complete, and that hall light is illuminated. The circuit that is completed, assuming, for illustration, that car No. 3 is at the upper terminal floor and that selective down light relay 3LD has operated, may be traced from wire 137, through wire 14'1, knife switch 3-163, selector brush 3-160, upper terminal floor selector contact 3-162, upper terminal floor hall light 3-465, contacts,3--LD91 of the selective down light relay, to wire 138. As was described with reference to the system of Figure 2, when the selective down light relay for a car operates, that car is the car that next receives the signal to start. Accord ingly, the upper terminal floor hall light for a car is illuminated only when that car is the next one to be dispatched. Thus, in the event, that that there should be more than one car at the upper terminal floor, prospective passengers are directed to the proper car.

If it is desired to notify the operator within a car at a terminal floor that his car is the next to be dispatched, and that prospective passengers are being directed to his car, a notification light for that terminal floor may be mounted within each car, and connected in parallel with the hall light at that terminal floor for the corresponding car. Such notification lights, 166 for the lower terminal floor, and 16''! for the upper terminalfloor, have been shown in dotted outline connected across the lower and upper terminal hall lights, respectively. As a result of this arrangement, the notification light for each car is lighted at the same time that the terminal floor hall light is lighted.

It is to be noted when a car is taken out of the control of the dispatching system by opening the knife switch 51 for that car, the hall and notification lights'are ordinarily rendered inoperative at the same time by opening the knife switch 163 for that car.

It may be desirable, under certain conditions, to definitely prevent the departure of a car from a terminal floor until the receipt by that car of a signal to start. These conditions may arise, for example, when the operators are careless or disobedient of instructions. In the event that an operator starts his car away from the terminal floor before receiving a signal to start, not only is that car out of schedule, but unbalance, or suspension of the timing, or both, may occur.

This is due to the fact that when a car departs before receiving a signal to start, the signal to start which. was intended for that car is given to the nextsucceeding car. Thus, two cars are started when it is the intention to start only one. Also, in the event that the next succeeding car does not depart within the definite time interval after the initiation of the signal to start intended for the preceding car, the timing operations are suspended. An arrangement for efi'ecting definite prevention of the departure of a car from a terminal floor until the receipt by that car oi Q.

signal to start is embodied in the system of Figures 7 and 8. Electromagnetic switches shown in Figures '7 and 8 for this purpose which are additional to those previously enumerated and described with reference to Figure 2 are designated as follows:---

.A-Up car holding relay B-Down car holding relay S-Car starting switch Y--Auxiliary up car holding relay Z--Auxiliary down car holding relay similar in construction and operation to the up car holding relay A, so for conciseness no detailed; description is made thereof.

The operator's control switch 13 for each car is illustrated for simplicity as mounting only the single contact 170. Also, for simplicity there is illustrated for each car only a single stationary contact 171 with whichthe movable contact 170 may engage upon the throwing over of the operators control switch to start the car. Connected between the stationary contact 171 for, each car and the wire 138 (connected to the negative main) is the actuating coil S88 of a car starting switch for the corresponding car. The energization oi the actuating coil of the car starting switch for a car causes, by contacts, circuits, relay and other apparatus not shown herein, the starting of that car. The energization of the car starting switch actuating coil S88 for a car upon the throwing over of the operator's control switch 13 for that car may occur, however, only when the contacts A94 and 1397 of the up and down car holding relays, respectively, for that car are in engagement. It is to be understood that the contacts 170 and 171, or their equivalent, are placed in the circuit controlling the starting of the car, and thus, in push-button-controlled elevators, for example, these contacts may be placed in the starting circuits controlled by the push buttons.

' A description of the operation of the apparatus from this point is believed to most readily describe the invention. When it is desired to definitely prevent the departure of the cars from the lower and the upper terminal floors until the receipt by the cars of the dispatch signals, knife switches 172 and 1'73 are closed. These, as with the other knife switches employed in the system, may be mounted upon the dispatch panel 16 or elsewhere so as to be readily accessible to the starter or other of flcial. The closing .of knife switch 1'72 contacts Y176, Y177, 27178, and Y179 engage to 15p 

